1. Field of the Invention
The present invention relates to a support frame with an adjustable mechanism. In particular, the present invention relates to a support frame that can adjust the linear displacement by changing the length of an air pressure bar and one end of the support frame is fastened with a display screen.
2. Description of Related Art
The slim electronic devices, such as plat computers, LCDs, LCD TVs, and plasma TVs, etc, can be installed at a variety of locations, such as walls, ceilings, or desks, etc. In order to meet different installation ways according to user's demands, a lot of support frames or hold frames for supporting or holding the electronic devices are developed.
The support frames for supporting the electronic devices can be divided into a stand type and a hold type. The stand type support frame usually is located on the desk and the height and the angle of the electronic device installed on the support frame can be changed. The hold type support frame usually is located on the wall, and the electronic device installed on the support frame can change the location and the angle by using a support arm to rotate the support arm on a horizontal surface along a vertical shaft or rotate the support arm on a vertical surface along a horizontal shaft.
However, the height of the support frame cannot be changed, or the angle of the support frame has to be changed as the height of the support frame is changed. Therefore, the support frame cannot perform the linear displacement. In other words, the displacement and the angle cannot be adjusted independently. Moreover, when the support frame is received, the support arm of the support frame cannot be adjacent to the wall. The dimension of the support frame being received cannot be reduced.
Reference is made to FIG. 1. The support frame of the prior art includes a fastening base 1a, a displacement part 2a, a locking part 3a, an joint part 4a, a support arm 5a and a carrier base 6a. The fastening base 1a includes a plate body 11a and a guiding rod 12a. The guiding rod 12a is located on one surface of the plate body 11a. Another surface of the plate body 11a is used for being firmly placed on the desk. The displacement part 2a includes a connection portion 21a and two pivoting ears 22a. The displacement part 2a is connected with the guiding rod 12a via the connection portion 21a. The connection portion 21a is locked with the guiding rod 12a via the locking part 3a. The joint part 4a includes a horizontal pivoting portion 41a and a vertical pivoting portion 42a. The horizontal pivoting portion 41a is pivoted between the pivoting ears 22a. The support arm 5a includes an arm body 51a, a first pivoting portion 52a and a second pivoting portion 53a. The first pivoting portion 52a and the second pivoting portion 53a are respectively located at two ends of the arm body 51a. The vertical pivoting portion 42a is pivoted with the first pivoting portion 52a. The carrier base 6a includes a base plate 61a and a pivoting portion 62a. The base plate 61a is used for combining with a LCD (not shown in the figure). The pivoting portion 62a is pivoted with the second pivoting portion 53a. 
As shown in FIG. 1, when the height is adjusted, the locking part 3a needs to be looses. Next, the LCD is adjusted to the desired height by manpower and then locking the locking part 3a. During the height is adjusted, the user needs to loose and lock the locking part 3a. It is inconvenient. Furthermore, after the locking part 3a is loosed, the user needs to support the LCD. It is inconvenient.